Superheterodyne receiving circuit



y 13, 1952 J. H. VAN WAGENINGEN 2,596,624

SUPERHETERODYNE RECEIVING CIRCUIT Filed July 16, 1946 III I II INVENTOR. e/OHANJIMJHK VAN HZGZMYWHT AGEIVZ r Patented May 13, 1 952 2,596,624 SUPERHETERODYNE,RECEIVING CIRCUIT "Johan Hendrik van Wageningen, -'Eindhoven, Netherlands, assignor to Hartford National Bank :and Trust Company, Hartford; Conn, as-

2,596,624 ICE .jtrustee;

Application J my 16, 1946, SerialNo."684;D33 Inthe Netherlands April 21, 19513 Sectioul, Bublic aw 69. Au u t-8.1% Patent expires April-21, l963 3 Claims. (Cl. 250-20) This invention relates to a supe'rheterodyne receiving circuit which. is designed both; for. the reception, of broadcasting signals having a com.- paratively smallbahd width and for the reception of short-wave signals having a comparasignals or frequency-modulated signals).

selectivity.

from 3 to 20-mc./sec.

length switch via comparatively long conductors and this results in undue couplings anddetunings of= these circuits. In addition, theme- ;chanical construction of the required w-switches becomes highly involved.

The invention'has for its object toobviate h e. di advanta s a th Purpos ma av abl h jf ac tha wh n r ei ins he r wave enals' h amp flwiionpe te d at frequency amplifier stage'is generally considerlengthof less than 10 meters. When receiving 5 tivelylarge band widthlforcXhmple television ably lower in connection with the large band widththan when receivingthe broadcasting sig- When receiving broadcasting signals the inmale sothat it is desirable to use alarge number termediatefrequency amplifier must have a small of intermediate-=irequency stages when receiving band width in order to achieve the required the short-wave signals thanwhen receiving the broadcasting signals.

In this case use wilibe made of a compara- According to the invention, one or more-intively' low intermediate frequency which is gentermediate-irequency amplifier stages are in use erally chosen in theneighbourhoodof 125 kilowhen receivingthe broadcasting signals as well cycles/sec. or of450 kilocycles/sec. The use of as when @receiving the short-wave signals, a higher intermediate frequency is generally unwhereas one or more other intermediate-fredesirable inter alia because in this case satisquency amplifier stages are in use only when factory trackingbetweenthe tuning of the oscilreceiving the short-wave signals, the changeof latory circuit and that ofthe preselection circonnections of the intermediatefrequency amcuits can no longer be obtained in a simple 2o plifier when changing-over-iromthe reception of the short-wave signalsto the reception of In contradistinction to this, when receiving thebroa'dcasting signals being effected exclufrequency or phase-modulated-signals or telesively by rendering inoperative the amplifier vision signals the large band widthrenders it valve 01' valves ofat least one of thelastmennecessary to use a comparatively high intertioned intermediate-frequency amplifier stages. mediate frequency,for example of the orderof In order that theinvention may be clearly understood and readily carriedinto effect it will Generally in, the case of a receiver designed now be described more fully with reference to for the reception ofboth kinds of signals the the acompanying drawing, in which oneemintermediate frequency amplifier shouldthere- 3o bodiment is illustrated. fore be adapted for the amplification of two The single figure of-thedrawi-ngshows the diiierdnt intermediate frequencies. In this case intermediate-frequencypart of a wireless-reit-shouldbe borne in mind thatthe-hlgh-inte1- ceiver designed both i forthe reception of. the mediate frequency usedin-the reception of; the normal;amplitude-modulated broadcasting sigshort-wave signals is comprised in the band nals and for the reception of frequencyorphaseof the' broadcasting waves so that for-;the purmodulated short-wave signals having -a wave pose of avoiding interference itisessential that thishighintermediate frequency shouldynot' be the broadcasting signals use is made of a comtransmitted by the intermediate frecpiency paratively low-intermediate frequency, for examplifier during-the reception of broadcasting 40 ample of 450 lsc;/sec.,- whereas for the-reception waves. This leads to the use of an intermediate of the short-wave signals acomparatively' high frequency amplifier whose connections can I be intermediate frequency, forexample of 10 me./ changed'andin which several circuits tuned sec. is used.

to the low intermediate frequency are replaced, The anode circuit of a -mixing valve In in by, means, of the wave length switch, by circuits cludes anoscillatory circuit z tuned to the high tuned to the-high intermediate-frequency and intermediateirequencyland an, oscillatory cirvice versa when changing over to the shortcuit 3 tuned to the: low intermediate. frequency. wave reception. If the-said high-intermediate The oscillatory circuit! iscoupled inductively frequency were also used for the, reception of to an-oscillatory-circuit I whichdsalso-tuned the broadcasting waves such a change of. conto the high intermediate'irequencyv and which nections would nevertheless also be required in is included in' thecontrohgridcircuit 0;? an inorder to alter the band width of the intermediate termediate frequency wamplifier :valve v 5. "The frequency amplifier. A disadvantage of the said anode circuit of. the tube- .5. includes. anoscilchange; of connections is that the intermediate latory circuit 6 which. is. tuned to. thelhig-h infrequency; circuits must be, connected to the wave termediate frequency and which is coupled inductively the similar oscillatory circuit I.

trol-grid circuit of an intermediate-frequency amplifier valve 9. The. anode circuit of the tube 9 comprises an oscillatory circuit Ill tuned to the high intermediate frequency and an oscillatory circuit ll tuned to the low intermediate frequency. The circuit I is coupled to a similar circuit which is included in the control grid circuit of a tube l2 acting as an amplitude limiter. The anode current of the tube 12 is supplied to a network I3 which acts in known manner as a frequency detector.

The circuit I I is coupled via a similar circuit to a diode M which serves for the detection of the broadcasting signals. A switch i5 coupled to the wavelength changing switch permits of supplying either the output voltage of the network I3 or the output voltage of the diode hi to the output terminals l6 and I7.

The cathode lead of the intermediate-frequency amplifier 5 includes, in the usual manner,

7 the parallel combination of a condenser it and tion to this, it will be possible for the intermediate-frequency amplifier to transmit a low intermediate frequency during the reception of the short-wave signals; since, however, in this case the high frequency part of the receiver is tuned to a frequency which differs widely from the low intermediate frequency this cannot lead to interference.

A control voltage for automatic gain control is supplied in the usual manner to the tubes 5 and 9 by way of the conductor 2 I.

What I claim is: V g V 1. A superheterodyne receiver circuit arrangement, comprising input circuit means for a first signal voltage of a relatively high given central frequency and for a second signal voltage of a relatively low given central frequency, first and second amplifier discharge tubes each having an input electrode system and an output electrode system, first resonant circuit means tuned to the central frequency of said first signal voltage and coupled to said input means and to the input electrode system of said first tube, second resonant circuit means tuned to the central frequency of said first signal voltage and intercoupling the output electrode system of said first tube and the input electrode system of said second tube, third resonant circuit means tuned to the central frequency of said second signal voltage and interconnecting said input means and the input electrode system of said second discharge tube to provide solely a'single stage amplifier for said second signal, means coupled to the output electrode system of said second discharge tube to demodulate said signal voltages, and means to selectively render said first tube inoperative when receiving said second signal voltage.

2. A superheterodyne receiver circuit arrangement, comprising input circuit means for a first signal voltage of a first given central frequency and for a second signal voltage of a second given central frequency lower than said first given central frequency, first and second amplifier discharge tubes each having an input electrode system and an output electrode system, first resonant circuit means tuned to the central frequency of said first signal voltage and coupled .to said input means and to the input electrode system of said first tube, second resonant circuit means tuned to the central frequency of said first signal voltage and intercoupling the output electrode system of said first tube and the input electrode system of said second tube, third resonant circuit means tuned to the central frequency of said second signal voltage and interconnecting said input means and the input electrode system of said second discharge tube to provide solely a single stage amplifier for said second signal, means coupled to the output electrode system of said second discharge tube to demodulate said signal voltages, and switch means included in one of the electrode systems of said first tube to selectively render said first tube inoperative when receiving said second signal voltage.

3. A superheterodyne receiver circuit arrangement for receiving a first signal voltage of' a first given central frequency and a second signal voltage of a second given central frequency lower than said first given central frequency, comprising first and second amplifier discharge tubes each having an input electrode system and an output electrode system, first and second oscillatory circuits tuned to said first and second central frequencies respectively, means to apply said first signal voltage to said first oscillatory circuit and said second signal voltage to said second oscillatory circuit, means to couple said first oscillatory circuit to the input electrode system of said first tube, a third oscillatory circuit tuned to said first central frequency and coupled to'the output electrode system of the said first tube. a fourth oscillatory circuit tuned to said first central frequency and coupled to said third oscillatory circuit and to the input electrode system of said second tube, a fifth oscillatory circuit tuned to said second central frequency and coupled to said second oscillatory circuit, means to couple said fourth and fifth oscillatory circuits in series to apply said second signal voltage to the input electrode system of said second tube, sixth and seventh oscillatory circuits tuned to said first and second central frequencies respectively and coupled to the output electrode system of said second tube, means coupled to said sixth oscillatory circuit to demodulate said first signal voltage,-means coupled to said seventh oscillatory circuit to demodulate said second signal voltage, and switch means to selectively render said first tube inoperative when receiving said second signal voltage.

J OI-IAN HENDRIK vAN WAGE'NINGEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Batchelor Nov. 10,1942 

